Reader's Digest version: friend's mother fell and couldn't get up. Just like the commercials. Friend asked me to look into a technological way of her mom being able to press a button on some sort of transmitter device to send SMS messages.

If the technology exists in the United States, I can't find it after a week of searching. Oh, there's plenty of *services* that will install a device that will contact *them*, but, why pay a service?

As I was thinking about this problem, I was pulling into my driveway. I hit my garage door opener. That got me to thinking about a device that would send an infrared or bluetooth signal to a receiving device. Once that receiving device receives that signal it'll initiate emails and / or SMS messages to a list.

In searching I came across a gent who used an Arduino to open and close his garage door by sending an SMS from his cell. He could check to see if it was open or closed also by SMS.

That got me to thinking: why couldn't you use a garage door opener key fob to send a signal to an Arduino? The key fob would be small, easily put on a lanyard that could be worn all the time, and waterproof, too (in case of a shower fall.)

Unfortunately, I don't have the technical abilities to pull off anything like this. I hope this is the correct place to place a posting like this, and I beg your indulgence if I've put it in the wrong location.

Yes its very feasible and not even terribly difficult. The keyfob enclosures are available ready made from several sources. Or, as you said, you could use a keyfob garage opener. The best way to send the SMS it to connect the Arduino to the Internet. You can send the SMS by sending email to the proper SMS gateway. Or you can just send email. You could even make it sound an alarm or control motorized locks in the door so emergency personnel can get in easily.

Thank you, Skyjumper. I agree, it doesn't seem the least bit difficult . . . for someone who knows what they're doing. The technology is there. It's just a matter of picking it up and putting it in the right sequence.

The steps appear to be:

** Sending unit (key fob, let's say) sends a signal to a receiving unit attached to the Arduino.** Receiving unit receives the signal and passes it along to the OS of the Arduino.** When the OS gets the nod from the receiving unit, it executes a script / program that sends emails / SMSs.

Unfortunately, I wouldn't know where to begin. I'm not a programmer by any stretch of the imagination.

Of course, this also brings up a question which might be borderline sacrilege here. (heh.) The Arduino is obviously a computer. Why couldn't a sending unit send a signal to a receiving unit to an existing PC / Mac? Perhaps I'm going about this the wrong way. Perhaps I'm trying to recreate the wheel when it already exists. Finding that wheel is proving elusive. Which is why I started investigating Arduino in the first place.

To restate: I'm looking to have a device built that can send out SMS messages upon receiving an IR signal.

It's purpose is just like those expensive monitoring services. "I've fallen and I can't get up!" Person presses a button. Monitoring service is contacted.

What I envision takes the monitoring service OUT of the equation. Person presses a button. Device receives signal. Device sends SMS messages to everyone on its notification list. Just really couldn't be any simpler.

Well, except it needs to be able to work even without AC power. (How's that for a new wrinkle?)

Believe it or not, I found almost *exactly* what I'm looking for . . . in Australia. They don't sell 'em in the United States. (I wrote to them and asked.) This is just about perfect.

I designed a monitor for the sump in my basement that sends an SMS via the Internet (ThingSpeak/Twitter) if either the power goes out or if the water in the sump is too high. The monitor uses 4xAA cells for backup power if the utility power goes out. My network gear (DSL modem, router) is powered by a fairly typical UPS unit.

This approach requires Internet service. A GSM modem could be substituted, that is probably a better and more direct approach for your specific application, that would require mobile phone service, and a UPS would probably be required there as well.

I'm not aware of how to send an SMS from a regular land line, but that'd be worth looking into.

I'm not aware of how to send an SMS from a regular land line, but that'd be worth looking into.

Hi Jack, I already contacted the OP before and had a very detailed talk on the quote I made to him , but he was looking for something way cheaper , The thing here everybody needs to understand who has not experienced sending sms or calls using the telephony system is that the cost of hardware is costly and is complex in making the system dependable , i have worked a lot with independent telephony cellular modules like SIM 300 etc and SMB5100 etc among other and have noted that the programming to have dependable real time systems with these is really tricky and involves considerable headache and hardwork so this project is going to be somewhat costly.

...really tricky and involves considerable headache and hardwork so this project is going to be somewhat costly.

Hmm, well, I suppose, could be, possibly.

For sure there has to be a paid-for service somewhere. It can be designed such that there is no separate service fee for the personal emergency transmitter, but it then has to piggyback on something else, be that a cellular service, internet service, or a land line (although if and how that is possible in the USA I am not certain of.)

Well, there are then complexities in terms of band operation and failure of connectivity and then frequent break in the service/connectivity requires writing clever code that ensure's the message goes definitely , I have even utilised the NEVER out GSM/GPRS shield from arduino and telefonica collaboration which is not already out commercially.

with all that the cost rises ,believe me.

EDIT:

Then power issues , when the SIM within the embedded system tries to connect to the network while making calls etc then it calls for a burst of more than 1 amp approx .

Interestingly I am not having such headaches with the system I am designing for a client that control access to vehicles over the GSM network using SMS based calls and commands. The same board also has accelerometers and an extended SPI interface to chatter with other modules in the collection. My client is using a simple GSM shield that I have placed onto a custom PCB along with a ATMerga328 and supporting bits and bobs ( i cannot be too specific as it would violate my NDA )

I'm not aware of how to send an SMS from a regular land line, but that'd be worth looking into.

Hi Jack, I already contacted the OP before and had a very detailed talk on the quote I made to him , but he was looking for something way cheaper , The thing here everybody needs to understand who has not experienced sending sms or calls using the telephony system is that the cost of hardware is costly and is complex in making the system dependable , i have worked a lot with independent telephony cellular modules like SIM 300 etc and SMB5100 etc among other and have noted that the programming to have dependable real time systems with these is really tricky and involves considerable headache and hardwork so this project is going to be somewhat costly.

EmbeddedAT .. From Concept to Prototype to ProductionElectronics and firmware design and project mentoringI do answer personal requests for help when accompanied with a PayPal receipt

@ Baines bunch , as I have already specifiedIit also depends over the carrier you choose some accept the development like some Sims are locked and some are open on all ports, also in Europe companies are more supportive with all this stuff developers do with their Sims in Asia if you call the customer care to unlock the ports on sim then they would never know what not are talking about and as such tech support is too weak also implementing sms is easy as to implementing GPRS .this is what I have experienced and worked out at another part of the world!

@ NI$HANT, Sorry but I have just gone through all the post by you in this thread and I can't seem to find the bit where you talk about carriers (apart from your reply to me), you do talk about bands, perhaps we have a misunderstanding of terms here.

You are right that SMS is an easy option but then not everywhere has GPRS and so in order to have a system that falls back to the lowest common denominator SMS over GSM is the obvious choice.

Why over complicate a system ?

"KISS" is the name of the game in cost effective development where future extensibility is not a show stopper.

I have no desire to get into a debate over this, i was just stating that I have not experienced the difficulties that you cite when explaining the complexities and subsequent cost of mobile communications development using either GPRS or GSM .

Perhaps i can help you to solve some of the issues you are having.

Cheers Pete.

EmbeddedAT .. From Concept to Prototype to ProductionElectronics and firmware design and project mentoringI do answer personal requests for help when accompanied with a PayPal receipt